A dark porous solid fuel, mainly carbon, formed as a pyrolysis or carbonisation product of coal, produced either as by-product of Town Gas production or as the main product of Coke Ovens – metallurgical or hard coke. Optimum Coke properties depend upon the end-use which include presently, the main energy supply and ore reducing agent in blast furnaces, and in former times a domestic and industrial smokeless fuel and a basic fuel for gas producers